This invention relates to devices for taking samples of body fluids from patients for subsequent examination in a clinical lab. More particularly, this invention relates to a specific configuration of evacuated tube with the vacuum in the tube being utilized to draw body fluid specimens from the body of a patient by a phlebotomist, nurse or doctor.
As practitioners in the art of blood draw procedures understand, it is most important that the vacuum in evacuated tubes utilized for that purpose be maintained at the proper level during storage for subsequent use. That is, these practitioners, during use of such evacuated tubes, insert one end of a double ended needle into the vein of a patient. The other end extends through an open ended holder for receiving, sequentially, a plurality of evacuated tubes. It is most important that this procedure be carried out efficiently and as rapidly as possible, as anyone will understand, since the technician or phlebotomist carrying out the procedure must contend with a patient having a needle stuck through their skin into a vein. If, for example, the vacuum is deficient in one tube during such a procedure, it entails subsequent removal of the tube and insertion of another tube which prolongs the unpleasant procedure involved.
This invention is directed particularly to a stopper-shield combination for sealing the open end of such body fluid collection tubes. That is, the tube, regardless of its make up or nature, must maintain the vacuum therein by a specific closure for that purpose. If the closure is defective or does not provide appropriate seal, the vacuum property deteriorates over time.
As a further consideration for the combination stopper-plastic cover or shield combinations currently utilized for body fluid collection tubes of the kind discussed herein, it is most important during subsequent examination, where samples of the material are being removed from the tubes that the insertion of a needle through the stopper for such withdrawal is relatively easily carried out. That is, if great effort is required to force a needle through the stopper, then the clinician in the laboratory may get involved with accidents wherein blood contamination may take place. Or simply the routine insertion of a great many needles through a great many stoppers entails more effort than should be required.
It is to this kind of situation that the present invention is directed. That is, this invention is directed to a specific configuration of elastomer stopper for sealing the closed end of an evacuated body fluid collection tube with a plastic shield or cover positioned thereover. It is routine to utilize a plastic shield over the elastomer stopper for several reasons. First, the plastic shield provides a gripping surface for easy removal of the elastomer stopper from the evacuated tube to overcome the force of the vacuum, and for removal of samples, as required in the laboratory. Moreover, if samples are to be removed by a needle, as discussed above, when the needle is removed, blood droplets may form on the top surface of the elastomer stopper. The shield provides an overhang over the top surface to contain any of these blood droplets or an aerosol of the liquid spurting out of the top of the stopper when the needle is being withdrawn.
Efforts have been made in the past to develop stopper plastic shield combinations for alleviating some of the problems discussed above. One such device is disclosed and claimed in U.S. Pat. No. 4,465,200, which covers a stopper-plastic shield combination with cooperating annular abutments so that the plastic shield easily lifts the stopper from the top of an evacuated tube. Moreover, this particular configuration includes an overhang of the plastic shield over the top surface of the rubber stopper to prevent exposure to blood droplets withdrawn with the withdrawal of a needle from the stopper. While the structure is successful in providing the characteristics desired, the configuration of stopper and shield provided with that combination is somewhat cumbersome in size and requires a substantial space for storing such tubes before and after use.
Other representative patents directed to problems of the kind discussed above include U.S. Pat. Nos. 4,187,952 and 4,186,840 which are both directed to combination peelable seal arrangements and plastic caps over the top of elastomer stoppers for the purpose of preserving the sterility thereof prior to use.
Further representative combination closures of the kind discussed herein include U.S. Pat. Nos. 3,460,702, 4,204,608; European Patent Publication No. 0102851 and European Patent Publication No. 0028411.
With this invention by contrast, a specific configuration of stopper plastic shield or cover combination is provided in which the specific configuration allows for dimensional reduction in the overall size of the closure. This allows for readily reduced storage space for such blood collection tubes both prior and after use.
Moreover, the combination closure of the invention herein reduces the stresses placed on the elastomer stopper, once it is inserted into the body fluid collection tube. Because of this, the user may use substantially less force to insert a needle through the elastomer stopper. As discussed above, this has the effect of reducing the overall effort in a daily environment handling many such tubes and inserting needles through the stoppers, but also it reduces the possibility of accidents simply because of the ease of insertion and withdrawal allowed with the invention here.
The results of this stopper-shield combination of the invention is achieved because the lower insertion portion of the stopper includes a plurality of vertically spaced alternating indentations and rings. The vertically spaced sealing rings inserted into the upper end of the tube provide spaced areas of sealing, while reducing the internal stresses in the stopper body.
Moreover, the upper flange of the stopper which extends out over the top of the tube of interest includes a plurality of circumferentially spaced protrusions. These protrusions cooperate with a plurality of ports or indentations in the plastic shield utilized with the stopper. By doing so, a proper positive connection is achieved between the plastic shield or cover and the related stopper while reducing the overall dimensions of the combination. The upper over-hang portion of the stopper is inserted in the plastic shield and twisted. This causes the protrusions on the stopper to move into place in the shield wall.
With the foregoing and additional objects in view, this invention will now be described in more detail, and other objects and advantages thereof will be apparent from the following description, the accompanying drawings, and the appended claims.